Supply and control of air for boiler and other furnaces.



' PATENTED APR. 7, 1908 W. s. HUBBARD. SUPPLY AND CONTROL OF AIR FOR BOILER AND OTHER FURNAGBSL.

APPLICATION FILED JUNE 2, 1906.

1H NORRXS PETERS co., wAsmlvcroN. B. c

UNITED sTAT Es PATENT OFFICE.

WILLIAM SAMMONS HUBBARD, OF LEICESTER, ENGLAND.

SUPPLY AND CONTROL OF AIR FOR BOILER AND OTHER FURNACES.

Specification of Letters Patent.

Patented April '7, 1908.

Application filed June 2, 1906. Serial No. 319,905.

leigh road, in the county borough of Leicester, England, in the United Kingdom of Great Britain and Ireland, have invented new and useful Improvements Relating to the Supply and Control of Air for Boiler and other Furnaces, of which the following is a specification.

My invention refers to improvements relating to the supply and control of air for boiler and other furnaces, and consists in providing means for controlling and regulating the. draft to the furnace, so as to obtain as perfect combustion as possible, and also comprises certain features of construction not found in apparatus for the same purpose now employed, and characterized by a novel form of slide valve by which the amount and direction of the draft to the furnace is controlled and regulated as desired as follows :'(a) under the fire bars, (6) under the fire bars and also through a passage or passages to the back of the bridge simultaneously, (0) through the passage or passages in the draft plate alone. I attain these objects by the mechanism illustrated in the accompanying drawing, in which Figure 1, is a front elevation, and Fig. 2 a longitudinal section (on line a, b, Fig. 1) of my improved apparatus as applied to a boiler furnace. Fig. 3 is a vertical section on line 0, d of Fig. '2, Fig. 4 is a plan showing the connections for actuating the valves, and Fig. 5 is a sectional detail.

Similar letters refer to similar parts throughout the several views.

In carrying my invention into effect the fire bars A are arranged as usual across the furnace, and the said fire bars are suitably carried on and above the draft plate B, thereby providing an inclosed air space or chamber B The said fire bars A (a few of which are shown) may be carried either on the draft plate B, as shown, or in any other suitable manner to prevent the air in the chamber from coming into contact with the boiler fiue. The said draft plate B may be supported on the bottom part of the fiue, or on projections fixed in or lying upon the flue, and extends from the front part of the boiler, to the back of the bridge.

The chamber B (formed by the fire bars A and draft plate B) has passed therethrough, one or more of the blowing tubes C which form air passages extending the whole length of the said chamber. The said tubes C are both supported in position by means of the flanges C C, bolted to a front plate D and at their rear end they pass through the plate E. The said tubes C at their front ends are preferably contracted inside at C so as to obtain a more concentrated draft, and they are also provided with rectangular slots C G on either side, so as to distribute the air, and the said tapered tubes C at their rear ends, are also reduced in area and bored through to provide a smooth surface for the slide valve F to be moved freely therein.- In the present instance the slide valves F, F, have a lateral movement imparted simultaneously to them by means of the bar G and rod H connected thereto. The bar G is free to move in the slots C C see Figs. 2, 4 and 5 With the slide valve or valves F in the posi tion shown in Fig. 2, air may pass from the passages C through the slots C and C and under the fire bars A, but when the valve or valves F are drawn slightly forward in the direction of the arrow, air may pass up the passage J at the back of the bridge, and through the fire bars simultaneously, and also through the slots C while, when the valve or valves F are drawn forward to their full extent, the ports C C are closed and the air passes straight through the tubes in passages F, F and up the passage J at the back of the bridge.

I would have it well understood that the air passage behind the bridge is provided with an inclined outlet which avoids any chance of dust or dirt being carried therein. Further I also protect the metal of which it is composed with fire bricks to preserve said outlet, and the air circulates away from the bridge in the direction of the gases from the main flue. Air is introduced by means of suitable steam jets or the like located at K at the front end of the tubes C.

I am aware that prior to this invention tubes have been used in boiler furnaces perforated and otherwise, in combination with fire bars, but I do not claim such combination broadly; but

I claim:

In a furnace provided with a fire box and ash pit, a bridge wall at the rear of the fire box and ash pit, a grate separating the fire box and ash pit, said bridge well being provided with a fine leading from the ash pit through the bridge Wall and being open at its rear, one or more conduits provided with perforations extending through the ash pit from front to rear and communicating With the flue in the bridge Wall, a slidable tube Within the rear end of each conduit adapted to seat Within the said flue to form a valve 10 and means extending to the front of the furnace connected to the slidable tubes to reciprocate them.

In witness whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

WILLIAM SAMMONS HUBBARD.

Witnesses:

' T. S. SHINLER,

WALTER W. BALL. 

